BACKGROUND
FIELD OF THE INVENTION
[0001] The present invention relates to a robot system and a method for picking a workpiece.
DISCUSSION OF THE BACKGROUND
[0002] Japanese Unexamined Patent Application Publication No.
08-336784 discloses what is called a multiple-picking object processor for use in a robot system
in which conveyors or similar devices convey workpieces and a robot holds the workpieces
to transfer the workpieces to another place.
[0003] In the multiple-picking object processor, the robot includes a plurality of holders
to hold a plurality of workpieces simultaneously in transferring the plurality of
workpieces to another place.
[0004] In many of such multiple-picking object processors, a predetermined order is determined
in advance for the holders to operate and hold the workpieces. The workpieces are
held in the order in which the workpieces are conveyed on the conveyor.
[0005] The contents of Japanese Unexamined Patent Application Publication No.
08-336784 are incorporated herein by reference in their entirety.
[0006] Japanese Unexamined Patent Application Publication No.
08-336784 leaves room for improvement in effective transfer of the workpieces.
[0007] Specifically, the robot may have to move over a long distance so as to hold the workpieces
due to the manner in which the workpieces are conveyed, such as the positions of the
workpieces on the conveyor. The elongated distance of movement of the robot may degrade
conveyance efficiency of the workpieces.
[0008] The present disclosure has been made in view of the above-described circumstances.
It is an object of the present disclosure to provide a robot system and a method for
picking a workpiece that ensure more efficient transfer of workpieces.
SUMMARY
[0009] According to one aspect of the present disclosure, a robot system includes a conveyor,
a robot, and a controller. The conveyor is configured to convey at least one workpiece.
The robot includes a plurality of holders configured to hold the at least one workpiece.
The controller is configured to control the robot to hold the at least one workpiece
conveyed on the conveyor and transfer the at least one workpiece to a predetermined
place using at least one holder among the plurality of holders. The controller includes
a divided area setter and an allocator. The divided area setter is configured to set
a plurality of divided areas on the conveyor in a width direction of the conveyor,
and is configured to store the plurality of divided areas in a storage. The allocator
is configured to allocate the plurality of holders respectively to the plurality of
divided areas so as to hold the at least one workpiece when the at least one workpiece
is conveyed in the plurality of divided areas.
[0010] The one embodiment ensures efficient transfer of workpieces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A more complete appreciation of the present disclosure and many of the attendant
advantages thereof will be readily obtained as the same becomes better understood
by reference to the following detailed description when considered in connection with
the accompanying drawings, wherein:
FIG. 1A is a schematic perspective view of a robot system according to an embodiment,
illustrating an arrangement configuration of the robot system;
FIG. 1B is a schematic diagram illustrating one round of transfer movement;
FIG. 1C is a schematic diagram illustrating a position of a robot hand in a basic
posture in relation to positions of divided areas;
FIG. 2A is a first schematic perspective view of a robot system, illustrating a picking
movement in a method according to a comparative example for picking a workpiece;
FIG. 2B is a second schematic perspective view of the robot system, illustrating the
picking movement in the comparative method for picking a workpiece;
FIG. 2C is a third schematic perspective view of the robot system, illustrating the
picking movement in the comparative method for picking a workpiece;
FIG. 3A is a first schematic perspective view of the robot system according to the
embodiment, illustrating a basic picking movement in a method according to the embodiment
for picking a workpiece;
FIG. 3B is a second schematic perspective view of the robot system according to the
embodiment, illustrating the basic picking movement in the method according to the
embodiment for picking a workpiece;
FIG. 3C is a third schematic perspective view of the robot system according to the
embodiment, illustrating the basic picking movement in the method according to the
embodiment for picking a workpiece;
FIG. 4A is a first schematic perspective view of the robot system according to the
embodiment, illustrating an exceptional picking movement in the method according to
the embodiment for picking a workpiece;
FIG. 4B is a second schematic perspective view of the robot system according to the
embodiment, illustrating the exceptional picking movement in the method according
to the embodiment for picking a workpiece;
FIG. 4C is a third schematic perspective view of the robot system according to the
embodiment, illustrating the exceptional picking movement in the method according
to the embodiment for picking a workpiece;
FIG. 5 is a block diagram illustrating the robot system according to the embodiment;
and
FIG. 6 is a flowchart of a procedure for processing performed by the robot system
according to the embodiment.
DESCRIPTION OF THE EMBODIMENTS
[0012] A robot system and a method for picking a workpiece according to an embodiment of
the present disclosure will be described in detail below with reference to the accompanying
drawings. The following embodiments are provided for exemplary purposes only and are
not intended to limit the present disclosure.
[0013] An outline of a robot system 1 according to the embodiment will be described with
reference to FIGs. 1A to 1C. FIG. 1A is a schematic perspective view of a robot system
1 according to this embodiment, illustrating an arrangement configuration of the robot
system 1. FIG. 1B is a schematic diagram illustrating one round of transfer movement.
FIG. 1C is a schematic diagram illustrating a position of a robot hand in a basic
posture in relation to positions of divided areas.
[0014] For ease of description, FIG. 1A illustrates a three-dimensional orthogonal coordinate
system including a Z axis with its vertically upward direction being assumed the positive
direction. This orthogonal coordinate system may also be illustrated in some other
drawings referred to in the following description.
[0015] As illustrated in FIG. 1A, the robot system 1 according to this embodiment includes
a conveyor 10, a robot 20, a detector 30, and a controller 40.
[0016] The conveyor 10 is a conveyance device that conveys workpieces W on a conveyance
path 11 from the upstream side toward the downstream side. In this embodiment, the
conveyor 10 is a belt conveyor. This configuration, however, should not be construed
in a limiting sense. The conveyor 10 may be any other conveyance device insofar as
the conveyance device is capable of conveying the workpieces W in a predetermined
conveyance direction. In this embodiment, the conveyance direction is the negative
direction of the X axis.
[0017] The robot 20 is an articulated robot secured on an installation object such as a
ceiling, a wall, and a floor. The robot 20 holds workpieces W conveyed on the conveyor
10 and transfers the workpieces W to another place. In this embodiment, the robot
20 transfers the workpieces W to a conveyor 50, which is parallel to the conveyor
10 (see the arrow 101 in FIG. 1A).
[0018] The robot 20 includes an arm distal end 21. To the arm distal end 21, the robot hand
to hold the workpieces W is attached.
[0019] The robot hand includes a plurality of holders 23a and 23b, and a support 22. The
holders 23a and 23b hold the workpieces W. The support 22 is turnably disposed on
the arm distal end 21 and supports the plurality of holders 23a and 23b.
[0020] The holders 23a and 23b hold workpieces W by sucking the workpieces W using a suction
device such as a vacuum pump. The robot 20 holds a plurality of workpieces W using
the holders 23a and 23b. The robot 20 holds and moves the workpieces W to above the
conveyor 50. Then, the suction force of the suction device is released to place the
workpieces W onto the conveyor 50.
[0021] Specifically, as illustrated in FIG. 1B, a plurality of workpieces W are sucked on
both the holders 23a and 23b. That is, the robot 20 uses both the holders 23a and
23b to transfer the plurality of workpieces W from the conveyor 10 to the conveyor
50 at once (see the arrow 102 in FIG. 1B).
[0022] After a round of this transfer movement, the robot 20 returns to its predetermined
"basic posture". From the "basic posture", the robot 20 starts a next round of transfer
movement to hold workpieces W.
[0023] As illustrated in FIG. 1C, in the "basic posture", the robot hand is positioned above
the conveyor 10 with the holders 23a and 23b, which are parallel to each other, aligned
in a direction approximately parallel to the "width direction" of the conveyor 10.
The "width direction" is approximately perpendicular to the conveyance direction of
the conveyor 10 (see FIGs. 1A and 1C).
[0024] On the conveyance path 11 of the conveyor 10, the robot 20 has a movable area WA.
The movable area WA is divided in advance in the "width direction" into divided areas
CA1 and CA2. The holder 23a is allocated to the divided area CA1, since the holder
23a is closest of the holders 23a and 23b to the divided area CA1 when the robot 20
is in its "basic posture". The holder 23b is allocated to the divided area CA2, since
the holder 23b is closest of the holders 23a and 23b to the divided area CA2 when
the robot 20 is in its "basic posture". This allocation is performed by an allocator
41c, which will be described later (see FIG. 5).
[0025] Thus, the holders 23a and 23b are assigned their own "territories", namely, the divided
areas CA1 and CA2, respectively. While in this embodiment the robot 20 includes two
holders, the robot 20 may include three or more holders.
[0026] The robot hand of the robot 20 may be any other robot hand insofar as the robot hand
is capable of holding the workpieces W. For example, the robot 20 may include a robot
hand to clamp, instead of suck, to hold the workpieces W.
[0027] In this embodiment, the robot 20 is a vertical articulated robot. This configuration,
however, should not be construed in a limiting sense. The robot 20 may be a horizontal
articulated robot, a parallel link robot, an orthogonal robot, or any other robot
insofar as the robot is capable of holding and transferring the workpieces W.
[0028] The detector 30 is disposed at a further upstream position on the conveyor 10 than
the robot 20. The detector 30 includes a camera 31, for example. The camera 31 picks
up an image of a predetermined area on the conveyance path 11 to detect a conveyance
situation in which the workpieces W are conveyed. The image picked up by the camera
31 is output to the controller 40 through a communication network (not illustrated)
such as a Local Area Network (LAN).
[0029] The controller 40 is coupled in a communicable manner to various elements such as
the conveyor 10, the robot 20, and the detector 30. It is noted that any form of connection,
wired or wireless, may be employed. The controller 40 includes various control units,
processors, and storages so as to control operations of the various elements coupled
to the controller 40.
[0030] For example, based on a job program acquired through an input device (such as a programming
pendant) or through an upper-level device, not illustrated, the controller 40 generates
a movement signal to cause the robot 20 to operate. Then, the controller 40 outputs
the movement signal to the robot 20 so as to control the movement of the robot 20.
[0031] The movement signal is generated in the form of, for example, a pulse signal to each
servomotor in each joint of the robot 20. A specific configuration of the controller
40 will be described later with reference to FIG. 5.
[0032] With the above-described configuration of the robot system 1 according to this embodiment,
the camera 31 picks up an image on the conveyance path 11 of the conveyor 10. Based
on the image picked up by the camera 31, the controller 40 acquires a conveyance situation
in which the workpiece W are conveyed on the conveyance path 11.
[0033] Based on the acquired conveyance situation, the controller 40 makes an instruction
to the robot 20 to make a transfer movement, which is to hold the workpieces W using
the holders 23a and 23b and transfer the workpieces W to the conveyor 50. In response
to the instruction from the controller 40, the robot 20 performs the transfer movement.
In the following description, the action of holding a workpiece W in transferring
workpieces W, that is, taking a workpiece W from the conveyor 10 will be referred
to as "picking".
[0034] Next, by referring to FIGs. 2A to 4C, a method for picking a workpiece using the
robot system 1 will be described in relation to a comparative method for picking a
workpiece.
[0035] FIGs. 2A to 2C are first to third schematic perspective views of the robot system,
illustrating a picking movement in the comparative method for picking a workpiece.
[0036] FIGs. 3A to 3C are first to third schematic perspective views of the robot system
1, illustrating a basic picking movement in the method according to this embodiment
for picking a workpiece. FIGs. 4A to 4C are first to third schematic perspective views
of the robot system 1, illustrating an exceptional picking movement in the method
according to this embodiment for picking a workpiece. For convenience of description,
like reference numerals designate corresponding or identical elements throughout FIG.
2A to FIG. 4C.
[0037] As illustrated in FIG. 2A, in the comparative method for picking a workpiece, a predetermined
order is determined in advance for the holders 23a and 23b to operate and pick workpieces
W. The workpieces W are picked in the order in which the workpieces W are conveyed
on the conveyor 10. In this example, none of the holder 23a or 23b has been used yet,
and the holder 23b is the first to be used (see the dashed circle M1 in FIG. 2A).
[0038] Specifically, as illustrated in FIG. 2B, when a workpiece W1 conveyed on the conveyor
10 is partial to the positive direction of the Y axis, the robot 20 picks the workpiece
W1 using the holder 23b even though the holder 23b is partial to the negative direction
of the Y axis. Then, as illustrated in FIG. 2C, when a workpiece W2 conveyed on the
conveyor 10 is partial to the negative direction of the Y axis, the robot 20 picks
the workpiece W2 using the holder 23a even though the holder 23a is partial to the
positive direction of the Y axis.
[0039] That is, in the comparative method for picking a workpiece, the robot 20 may have
to move over a long distance in the picking movement due to, for example, the positions
of the workpieces W on the conveyor 10 (see the arrow 201 in FIG. 2B and the arrow
202 in FIG. 2C). Because of the elongated distance of movement of the robot 20, the
comparative method for picking a workpiece may degrade conveyance efficiency of the
workpieces W.
[0040] In view of this, in the method according to this embodiment for picking a workpiece,
the holders 23a and 23b are assigned their own territories, namely, the divided areas
CA1 and CA2, respectively.
[0041] Specifically, as illustrated in FIG. 3A, in the method according to this embodiment
for picking a workpiece, the holder 23a is allocated to the divided area CA1 as the
holder 23a's territory, and the holder 23b is allocated to the divided area CA2 as
the holder 23b's territory.
[0042] As illustrated in FIG. 3B, a workpiece W1 conveyed on the conveyor 10 is partial
to the positive direction of the Y axis and enters the divided area CA1. The robot
20 picks the workpiece W1 using the holder 23a considering that the holder 23a is
similarly partial to the positive direction of the Y axis. As illustrated in FIG.
3C, a workpiece W2 conveyed on the conveyor 10 is partial to the negative direction
of the Y axis and enters the divided area CA2. The robot 20 picks the workpiece W2
using the holder 23b considering that the holder 23b is similarly partial to the negative
direction of the Y axis.
[0043] Thus, the method according to this embodiment for picking a workpiece shortens the
distance involved in the picking movement (see the arrow 301 in FIG. 3B and the arrow
302 in FIG. 3C), as compared with the comparative method for picking a workpiece.
That is, the method according to this embodiment for picking a workpiece improves
efficiency in the conveyance of the workpieces W, that is, ensures more efficient
transfer of the workpieces W.
[0044] FIGs. 3A to 3C illustrate a basic picking movement in the method according to this
embodiment for picking a workpiece. It is possible for workpieces W to be continuously
partial to one side of the conveyor 10. In this case, the method for picking a workpiece
according to this embodiment uses an exceptional picking movement.
[0045] For example, as illustrated in FIG. 4A, assume that workpieces W1 to W3 are continuously
partial to the positive direction of the Y axis of the conveyor 10, that is, the workpieces
W1 to W3 are about to enter the divided area CA1.
[0046] In this case, as illustrated in FIG. 4B, the method according to this embodiment
for picking a workpiece first uses the above-described basic picking movement to pick
the workpiece W1, which has entered the divided area CA1, using the holder 23a.
[0047] Then, the workpiece W2 subsequently enters the divided area CA1 and is picked exceptionally
by the holder 23b when the holder 23b is not being used, even though the holder 23b
is originally in charge of the divided area CA2 (see the dashed circle M2 in FIG.
4C).
[0048] Thus, even when workpieces W are continuously partial to one side of the conveyor
10, all the workpieces W are reliably transferred, without any one workpiece W being
missed in picking.
[0049] The workpieces W1 and W2 in the state illustrated in FIG. 4C are transferred to the
conveyor 50. Then, a workpiece W3 and subsequent workpieces W are picked in the above-described
basic picking movement. That is, in the method according to this embodiment for picking
a workpiece, in the case where workpieces W are continuously partial to one side of
the conveyor 10, the movement distance involved in the picking of these workpieces
W temporarily increases (see the arrow 402 in FIG. 4C). In the other cases, however,
the basic picking movement is used (see the arrow 401 in FIG. 4B). This configuration
improves conveyance efficiency.
[0050] Next, by referring to FIG. 5, a block configuration of the robot system 1 according
to this embodiment will be described. FIG. 5 is a block diagram illustrating the robot
system 1 according to this embodiment. It is noted that FIG. 5 only illustrates those
components necessary for description of the robot system 1, omitting those components
of general nature.
[0051] The following description by referring to FIG. 5 will mainly focus on the internal
configuration of the controller 40, and may occasionally simplify or omit the components
that have been already described by referring to, for example, FIG. 1A.
[0052] As illustrated in FIG. 5, the controller 40 includes a control unit 41 and a storage
42. The control unit 41 includes a conveyor controller 41a, a divided area setter
41b, an allocator 41c, a situation acquirer 41d, and an instructor 41e.
[0053] The storage 42 is a storage device such as a hard disk drive and a non-volatile memory,
and includes divided area setting information 42a, divided area information 42b, and
allocation information 42c.
[0054] It is noted that not all the elements of the controller 40 illustrated in FIG. 5
need to be arranged within the single controller 40. Another possible embodiment is
that at least one of the divided area setting information 42a, the divided area information
42b, and the allocation information 42c stored in the storage 42 is stored in an inner
memory of the robot 20. Still another possible embodiment is that at least one of
the divided area setting information 42a, the divided area information 42b, and the
allocation information 24c is stored in an upper-level device upper than the controller
40, and acquired as necessary from the upper-level device by the controller 40.
[0055] A non-limiting example of the control unit 41 is a Central Processing Unit (CPU)
that is in charge of overall control of the controller 40. The conveyor controller
41a controls the conveyor 10, which is arranged to pass through a movable area WA
of the robot 20, to convey workpieces W to the movable area WA of the robot 20.
[0056] The divided area setter 41b sets the imaginary divided areas CA1 and CA2 (see FIGs.
1A and 1C) on the conveyor 10 based on the divided area setting information 42a, and
stores the divided areas CA1 and CA2 as the divided area information 42b.
[0057] The divided area setting information 42a is necessary information in setting the
divided areas CA1 and CA2, and includes the position and dimensions of the movable
area WA of the robot 20, the width of the conveyor 10, and the number of holders of
the robot hand.
[0058] The divided area information 42b includes a result of setting by the divided area
setter 41b such as the positions and dimensions of the divided areas CA1 and CA2.
[0059] Based on the divided area information 42b, the allocator 41c allocates the holders
23a and 23b respectively to the divided areas CA1 and CA2 so as to hold a workpiece
W conveyed in the divided areas CA1 and CA2. In other words, the allocator 41c assigns
the holders 23a and 23b their own basic territories.
[0060] Also, the allocator 41c stores a result of the allocation as the allocation information
42c. That is, the allocation information 42c relates the divided areas CA1 and CA2
respectively to the holders 23a and 23b.
[0061] Based on an image received from the camera 31, the situation acquirer 41d acquires
a conveyance situation in which the workpieces W are conveyed. While in this embodiment
the detector 30 includes the camera 31, the detector 30 may include any other device
for the purpose of detecting the conveyance situation in which the workpieces W are
conveyed.
[0062] For example, the detector 30 may include photoelectric sensors and an encoder of
the conveyor 10. Based on information received from these devices, the situation acquirer
41d is also capable of acquiring a conveyance situation in which the workpieces W
are conveyed. The situation acquirer 41d notifies the instructor 41e of a result of
the acquisition.
[0063] In response to the result of the acquisition received from the situation acquirer
41d, in response to availability of the holders 23a and 23b received from the holders
23a and 23b, and in response to the allocation information 42c, the instructor 41e
instructs the robot 20 to make a movement to transfer the workpieces W.
[0064] Specifically, unless the workpieces W are conveyed continuously in either the divided
area CA1 or the divided area CA2, the instructor 41e instructs the robot 20 to hold
and transfer the workpieces W in the above-described basic picking movement (see FIGs.
3A to 3C).
[0065] Alternatively, when the workpieces W are conveyed continuously in either the divided
area CA1 or the divided area CA2, the instructor 41e instructs the robot 20 to hold
and transfer the workpieces W in the above-described exceptional picking movement
(see FIGs. 4A to 4C).
[0066] When one round of transfer movement is complete, the instructor 41e instructs the
robot 20 to take its basic posture.
[0067] In the description by referring to FIG. 5, the divided area setter 41b sets the divided
areas CA1 and CA2 based on the divided area setting information 42a. This configuration,
however, should not be construed in a limiting sense. Another possible embodiment
is that the divided area setter 41b divides an image picked up by the camera 31 into
the divided areas CA1 and CA2 in the width direction of the conveyor 10, and stores
the divided areas CA1 and CA2 as the divided area information 42b.
[0068] Next, by referring to FIG. 6, a procedure for processing performed by the robot system
1 according to this embodiment will be described. FIG. 6 is a flowchart of the procedure
for processing performed by the robot system 1 according to this embodiment.
[0069] As illustrated in FIG. 6, the controller 40 controls the conveyor 10 to convey workpieces
W through the movable area WA of the robot 20 (step S101). The conveyor 10 is controlled
by the conveyor controller 41a to convey the workpiece W until the completion of work.
It will be readily appreciated that this embodiment is implementable without the control
of changing the conveyance speed of the conveyor.
[0070] Next, the detector 30 detects a conveyance situation in which the workpieces W are
conveyed on the conveyor 10 (step S102). Then, based on the conveyance situation acquired
by the situation acquirer 41d, the instructor 41e identifies the divided area, CA1
or CA2, to which a workpiece W corresponds (step S103).
[0071] Next, the instructor 41e identifies the holder, 23a or 23b, that is allocated to
the divided area, CA1 or CA2, of interest (step S104). For the sake of description,
assume that the instructor 41e identifies the holder 23a.
[0072] Then, the instructor 41e determines whether the identified holder 23a is not being
used (step S105). When the holder 23a is not being used ("Yes" at step S105), the
instructor 41e operates the robot 20 to hold the workpiece W using the holder 23a
(step S106).
[0073] When the holder 23a is in use ("No" at step S105), the instructor 41e determines
whether the other holder, namely, the holder 23b is not being used (step S107).
[0074] When the holder 23b is not being used ("Yes" at step S107), the instructor 41e operates
the robot 20 to hold the workpiece W using the holder 23b (step S108).
[0075] When the holder 23b is in use ("No" at step S107), which means that both the holders
23a and 23b are in use, the instructor 41e operates the robot 20 to transfer the workpieces
W held by the holders 23a and 23b to the conveyor 50, and then to hold the workpiece
W using the holder 23a (step S109).
[0076] Then, a determination is made as to whether the work is complete (step S110). When
the work is complete ("Yes" at step S110), the processing ends. When the work is not
complete ("No" at step S110), the controller 40 repeats the processing that starts
from step S102.
[0077] As has been described hereinbefore, the robot system according to this embodiment
includes the conveyor, the robot, and the controller. The conveyor conveys workpieces.
The robot includes the plurality of holders to hold the workpieces.
[0078] The controller controls the robot to make a movement to hold a workpiece conveyed
on the conveyor using one of the holders and to transfer the workpiece to a predetermined
place. The controller includes the divided area setter and the allocator.
[0079] The divided area setter sets the plurality of divided areas on the conveyor in the
width direction of the conveyor and stores the divided areas in the storage. The allocator
allocates the holders respectively to the divided areas so as to hold the workpiece
when the workpiece is conveyed in the divided areas.
[0080] With this configuration, the robot system according to this embodiment ensures efficient
transfer of the workpieces.
[0081] In this embodiment, the robot makes the exceptional picking movement in an attempt
to eliminate or minimize missed picking of the workpieces. This configuration, however,
should not be construed in a limiting sense. Another possible embodiment is to add
the control of changing the conveyance speed of the conveyor.
[0082] Obviously, numerous modifications and variations of the present disclosure are possible
in light of the above teachings. It is therefore to be understood that within the
scope of the appended claims, the present disclosure may be practiced otherwise than
as specifically described herein.
- 1
- Robot system
- 10
- Conveyor
- 11
- Conveyance path
- 20
- Robot
- 21
- Arm distal end
- 22
- Support
- 23a
- Holder
- 23b
- Holder
- 30
- Detector
- 31
- Camera
- 40
- Controller
- 41
- Control unit
- 41a
- Conveyor controller
- 41b
- Divided area setter
- 41c
- Allocator
- 41d
- Situation acquirer
- 41e
- Instructor
- 42
- Storage
- 42a
- Divided area setting information
- 42b
- Divided area information
- 42c
- Allocation information
- 50
- Conveyor
- CA1, CA2
- Divided area
- WA
- Movable area
1. A robot system (1),
characterized by:
a conveyor (10) configured to convey at least one workpiece;
a robot (20) comprising a plurality of holders (23a, 23b) configured to hold the at
least one workpiece; and
a controller (40) configured to control the robot (20) to hold the at least one workpiece
conveyed on the conveyor (10) and transfer the at least one workpiece to a predetermined
place using at least one holder (23a, 23b) among the plurality of holders (23a, 23b),
the controller (40) comprising:
a divided area setter (41b) configured to set a plurality of divided areas on the
conveyor (10) in a width direction of the conveyor (10), and configured to store the
plurality of divided areas in a storage (42); and
an allocator (41c) configured to allocate the plurality of holders (23a, 23b) respectively
to the plurality of divided areas so as to hold the at least one workpiece when the
at least one workpiece is conveyed in the plurality of divided areas.
2. The robot system (1) according to claim 1, further comprising a detector (30) configured
to detect a conveyance situation in which the at least one workpiece is conveyed on
the conveyor (10),
wherein a first holder (23a, 23b) among the plurality of holders (23a, 23b) is allocated
to a first divided area among the plurality of divided areas to hold the at least
one workpiece when the at least one workpiece is conveyed in the first divided area,
and
wherein when the detector (30) detects another workpiece being conveyed to the first
divided area while the first holder (23a, 23b) is holding the at least one workpiece
in the first divided area, and when a second holder (23b, 23a) that is among the plurality
of holders (23b, 23a) and that is not allocated to the first divided area is not being
used, the controller (40) is configured to control the robot (20) to hold the another
workpiece in the first divided area using the second holder (23b, 23a).
3. The robot system (1) according to claim 1 or 2,
wherein the plurality of holders (23a, 23b) are parallel to each other relative to
a robot hand of the robot (20), and
wherein when the robot (20) holds the at least one workpiece, the controller (40)
is configured to control the robot (20) to take a basic posture in which the robot
hand is positioned above the conveyor (10) with the plurality of holders (23a, 23b)
aligned in a direction parallel to the width direction of the conveyor (10).
4. The robot system (1) according to claim 3, wherein when the robot (20) is in the basic
posture, the allocator (41c) is configured to allocate one holder (23a, 23b) among
the plurality of holders (23a, 23b) to one divided area among the plurality of divided
areas that is closest to the one holder (23a, 23b).
5. A method for picking a workpiece,
characterized by:
conveying at least one workpiece using a conveyor (10) through a movable area of a
robot (20) comprising a plurality of holders (23a, 23b);
detecting a conveyance situation in which the at least one workpiece is conveyed on
the conveyor (10);
identifying, based on the conveyance situation, a divided area to which the at least
one workpiece corresponds from among a plurality of divided areas of the conveyor
(10) that are divided in a width direction of the conveyor (10); and
operating the robot (20) to hold the at least one workpiece using one holder (23a,
23b) among the plurality of holders (23a, 23b) that is allocated to the divided area.
6. The method according to claim 5, wherein when the detecting step detects another workpiece
being conveyed to the divided area while the one holder (23a, 23b) is holding the
workpiece in the divided area, and when another holder (23b, 23a) that is among the
plurality of holders (23b, 23a) and that is not allocated to the divided area is not
being used, the operating step comprises operating the robot (20) to hold the another
workpiece in the divided area using the another holder (23b, 23a).